Introduction[edit | edit source]
Anabolic resistance is defined by a blunted stimulation of muscle protein synthesis rates (MPS) (particularly myofibrillar protein) to common anabolic stimuli in skeletal muscle tissue eg dietary protein and exercise.
Anabolic resistance is responsible, in part, for skeletal muscle atrophy with ageing, muscle disuse, and during disease states.
Image 1: Protein shake and dumbbells
Physical Activity[edit | edit source]
A strategy to in part offset the age-related loss of muscle mass is to encourage the older population to maintain, or increase, daily habitual physical activity (e.g., sweeping, gardening, grocery shopping, etc.). Recent work supports the idea that increasing habitual physical activity improves the postprandial muscle protein synthetic response to food intake in the elderly.
Consistent with this idea that habitual physical activity is important for maintaining a normal postprandial muscle protein synthetic response to food intake, research shows that anabolic resistance also develops following inactivity or muscle disuse in young adults. eg a blunted muscle protein synthetic response to protein provision can be induced in young adults by simply unloading the muscle for as little as 10 days. This may explain the reported anabolic resistance of muscle protein synthesis in the elderly. Some researchers have speculated that short successive periods of muscle disuse, because of sickness or recurrent hospitalisation, may be at the root of the age-related loss of muscle mass.
Gut-Muscle Axis[edit | edit source]
Recent observations highlight the gut-muscle axis as a physiological target for combatting anabolic resistance and reducing risk of sarcopenia. Research suggests a link exists between the gut microbiota and muscle atrophy.
Prospective lifestyle approaches that target the gut-muscle axis to mitigate sarcopenia risk include:
- Increasing dietary fibre intake that promotes the growth and development of gut bacteria, thus enhancing the production of short-chain fatty acids (SCFA). SCFA are a major player in maintenance of gut and immune homeostasis.
- Prebiotic/probiotic/symbiotic supplementation also generates SCFA and may mitigate low-grade inflammation in older adults via modulation of the gut microbiota.
- Preliminary evidence also highlights the role of exercise in increasing the production of SCFA.
Hence lifestyle approaches that combine diets rich in fibre and probiotic supplementation with exercise training may serve to produce SCFA and increase microbial diversity, and thus may target the gut-muscle axis in mitigating anabolic resistance in older adults.
Image R: Mediterranean diet foods
Protein Intake and Muscle Function in Older Adults[edit | edit source]
Aside from physical activity status, total daily protein intake appears to be the most important determinant of anabolic resistance and sarcopenia.
- Seniors may need 1.0-1.3 grams of protein for every kilogram of body weight. eg if you weight 82 kg this could mean consuming 80-104 grams of protein every day, regardless of your calorie intake.
- The current protein RDA does not appear to meet the optimal protein requirements for older people to maintain skeletal muscle mass. Given that the reduced ability of dietary protein to stimulate muscle protein synthesis (MPS), increasing amounts of protein have been shown to result in better preservation of muscle mass.
Image R: Resistance exercise stimulates a prolonged elevation of MPS that can remain elevated for at least 48 h (dotted line).
"Protein ingestion at any point during this enhanced period of ‘anabolic potential’ will have an additive effect to these already elevated exercise mediated rates (solid lines)."
Consuming sufficient high-quality (i.e., leucine rich) protein in concert with resistance exercise (RE) is the most well-supported, determinant to improve, or at least maintain, skeletal muscle mass and function with advancing age. Despite the importance of leucine content in triggering and sustaining an optimal muscle protein synthesis (MPS) response, leucine supplementation alone is unlikely to confer a significant benefit for skeletal muscle.
See further here
The Role of Nutritional bases Strategies[edit | edit source]
Creatine and developing nutrition-based strategies appear to provide valuable tools to overcome anabolic resistance in concert with RE-induced adaptations.
In contrast, evidence to support vitamin D (outside of preventing deficiency/insufficiency), NSAID, and antioxidant supplementation to overcome anabolic resistance and augment RT adaptations are lacking.
Physiotherapy[edit | edit source]
As physical exercise specialist we need to educate those at risk or in a state of anabolic resistance eg seniors, diabetics.
Educate clients re: To build lean body mass, they need to make sure they keep their body in an anabolic state through nutrition, proper training and rest.
See these page to name a few
- Resistance exercises
- Physical Activity in Older Adults
- Muscle Proteins
- Physical Activity as an Anti-Aging Medicine
- Muscle Function and Protein
- Exercise and Protein Supplements
References[edit | edit source]
- Paulussen KJ, McKenna CF, Beals JW, Burd NA. Anabolic resistance of muscle protein turnover comes in various shapes and sizes. Frontiers in Nutrition. 2021;8:115.Available:https://www.frontiersin.org/articles/10.3389/fnut.2021.615849/full (accessed 10.12.2021)
- Morton RW, Traylor DA, Weijs PJ, Phillips SM. Defining anabolic resistance: implications for delivery of clinical care nutrition. Current opinion in critical care. 2018 Apr 1;24(2):124-30.Available: https://pubmed.ncbi.nlm.nih.gov/29389741/(accessed 10/12/2021)
- Burd NA, Gorissen SH, Van Loon LJ. Anabolic resistance of muscle protein synthesis with aging. Exercise and sport sciences reviews. 2013 Jul 1;41(3):169-73.Available: https://journals.lww.com/acsm-essr/Fulltext/2013/07000/Anabolic_Resistance_of_Muscle_Protein_Synthesis.6.aspx (accessed 10.12.2021)
- Prokopidis K, Chambers E, Ni Lochlainn M, Witard OC. Mechanisms Linking the Gut-Muscle Axis With Muscle Protein Metabolism and Anabolic Resistance: Implications for Older Adults at Risk of Sarcopenia. Frontiers in physiology. 2021:1910.Available: https://www.frontiersin.org/articles/10.3389/fphys.2021.770455/full(accessed 10.12.2021)
- Tan J, McKenzie C, Potamitis M, Thorburn AN, Mackay CR, Macia L. The role of short-chain fatty acids in health and disease. Advances in immunology. 2014 Jan 1;121:91-119.Available:https://pubmed.ncbi.nlm.nih.gov/24388214/ (accessed 10.12.2021)
- McKendry J, Currier BS, Lim C, Mcleod JC, Thomas AC, Phillips SM. Nutritional supplements to support resistance exercise in countering the sarcopenia of aging. Nutrients. 2020 Jul;12(7):2057. Available: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7399875/(accessed 10.12.2021)